histogenetic, [213];
ovogenetic, [213], [230], [243];
Nussbaum, on heredity, [172], [195], [206];
on regeneration amongst Infusoria, [185], [200].
Obelia, origin of germ-cells of, [208].
Obersteiner, on inheritance of epilepsy in guinea pigs, [311], [313].
Ophiostomum, karyokinesis in ovum of, [368].
Orgyia, [44].
Orth, on the transmission of acquired characters, [411].